Crate prefer 

prefer

A lightweight library for managing application configurations with support for multiple file formats.

prefer helps you manage application configurations while providing users the flexibility of using whatever configuration format fits their needs.

no_std Support

This crate supports no_std environments with alloc. The core types (ConfigValue, FromValue, ValueVisitor) work without std. Enable the std feature for file I/O, async loading, and format parsers.

Features

• no_std compatible: Core types work with just alloc
• Format-agnostic: Supports JSON, JSON5, YAML, TOML, INI, and XML (with std)
• Automatic discovery: Searches standard system paths for configuration files (with std)
• Async by design: Non-blocking operations for file I/O (with std)
• File watching: Monitor configuration files for changes (with std)
• Dot-notation access: Access nested values with "auth.username"
• No serde required: Uses a lightweight FromValue trait instead

Examples

use prefer::load;

#[tokio::main]
async fn main() -> prefer::Result<()> {
    // Load configuration from any supported format
    let config = load("settings").await?;

    // Access values using dot notation
    let username: String = config.get("auth.username")?;
    println!("Username: {}", username);

    Ok(())
}

Re-exports

pub use error::Error;

pub use error::Result;

pub use value::ConfigValue;

pub use value::FromValue;

pub use visitor::SeqAccess;

pub use visitor::ValueVisitor;

pub use builder::ConfigBuilder;

pub use config::Config;

pub use source::EnvSource;

pub use source::FileSource;

pub use source::LayeredSource;

pub use source::MemorySource;

pub use source::Source;

Modules

builder

Configuration builder for composing multiple sources.

config

Core configuration types and methods.

discovery

Configuration file discovery across standard system paths.

error

Error types for the prefer library.

formats

Configuration file format parsers.

source

Configuration source abstraction.

value

Configuration value types and conversion traits.

visitor

Visitor pattern for configuration value traversal.

watch

File watching functionality for configuration files.

Functions

load

Load a configuration file by name.

watch

Watch a configuration file for changes.